I'm shotting a Win. M 70LA, Choate USS w/bipod, Nikon Buckmaster 6-18x40mm w/SF, BDC and 4" shade, factory trigger as light as it will go.

Loading Win. once fired brass, neck sized, flash holes debured, cut to length and camfered. 59 gr. IMR 4350, Win. mag. primers, and Speer Gold Match 168 gr. BT.

I went shooting yesterday and this morning. yesterday I was shooting all 59 gr. and grouping about .5" w/ 3 shots at 100 yds.
Today I was shooting 58.5 gr. and 59.5 gr. and grouping about 3/4" - 1".

So I think I have found my charge, I now want to play with bullet seating depth. What is the best way to measure BSD? How much should I change it at a time?

Try using a Stoney Point Comparator to measure over all length from the ogive. I would start at .060 in. and shorten by .010 in. at a time until I had found the "magic" jump.

Geronimo

Geronomo explained it well.

You may want to try Win standard large rifle primers and FC match primers, as opposed to altering seating depth. You have got a really good load, but I notice that you are using WLMR primers. Generally, mag primers aren't needed for the 30-06 with 4350, although I see you are in Michigan. It is relatively easy to try different primers and five shots with each type will tell you what you want to know.

By the way, 59gr of IMR4350 and a mag primer is equivalent to about 60.5 grains of powder. I generally stop at 57gr and a regular primer under my 180gr Noslers. Kudude

quote:

Originally posted by kudude:
Geronomo explained it well.

You may want to try Win standard large rifle primers and FC match primers, as opposed to altering seating depth. You have got a really good load, but I notice that you are using WLMR primers. Generally, mag primers aren't needed for the 30-06 with 4350, although I see you are in Michigan. It is relatively easy to try different primers and five shots with each type will tell you what you want to know.

By the way, 59gr of IMR4350 and a mag primer is equivalent to about 60.5 grains of powder. I generally stop at 57gr and a regular primer under my 180gr Noslers. Kudude

I use the mag primers b/c this rifle still sees a good amount of time in the woods durning deer season, its gets real cold some mornings.

Has anyone ever had a primer fail b/c of cold weather. My manuals recommend mag primers if used below +20* F.

Thanks for your input fellas.

I run 57 gr. of 4350 behind my 165 gr. Nosler Ballistic Tips. I hunt in northern South Dakota, never had a failure, even at -20.
Selmerfan

cjaholic,
I probably hunt areas similar to yours. I have always used Federal 210's in my '06s and have never failed to have one go bang when the trigger was pulled...even in the UP.

Geronimo

I used WLR primers with 59 gr IMR4350 under 150 gr Hornady SPs for years with no trouble. I think you`ll find ball powders to be more of a problem then extruded at cold temps, in `06 sized cases on down.

Without question, measuring ogive for BSD is best approach. One you have this measurement it's simple to change bullets and maintain sweet-spot.

Also take a look at the Davidson Depth Checker. I know Sinclair International carries it.

Start with a un-primed prepared dummy case. Seat a bullet with the seating die just to get it started deep enough in the case then chamber and close bolt. This will give you length to lands. I back off .030" from this point.

Ok, so I should keep everything the same and change primers and see how it shoots. Maybe shoot 5-shot groups.

I dont know what the BSD is right now, I set the die up as RCBS said and left it alone. Should I go right to .030" to start? If so where from there?

Thanks for all the help.

quote:

Has anyone ever had a primer fail b/c of cold weather. My manuals recommend mag primers if used below +20* F.

You might be careful with that load at 100°F.
58.5 grains of IMR4350 mashed primers pretty flat in my rifle at that temp.

I'll tell you one thing, when I have a hunting gun shooting .5" groups, I don't mess too much with that bad boy!!

Geronimo

.5 inch groups out of a hunting rifle? I was thinking like you Geronimo; pretty darn good hunting accuracy. I wouldn't mess with it either. Merg

Thanks for all your input.

Yes, I still hunt with this rifle but I have never heard of a hunting rifle or load being to accurate. This rifle is only being used to hunt b/c of limited funds to buy a new sporter. It spends about 98% of its time at the range. I think this rifle/load combo has more potential. I understand where ya'll are coming from and agree this load is more than efficient for hunting but why not finish working with the load to see what its capable of?

Once again thanks for helping.

I'm not a fan of the Stoney Point/Hornady Thingies. Way too prone for error and non-repeatable measurements.

quote:

Originally posted by cjaholic:
...What is the best way to measure BSD? How much should I change it at a time?

That would be using the old, time-proven, never-fail, easily-repeatable, Cleaning Rod Method. Once you determine the OCL for the Kiss-the-Lands distance, convert from OCL to ODL and it is easy to make the changes to Seating Depth.

Try changing the Seating Depth 0.010" or even 0.005" to Fine Tune your Final Load.

Best of luck to you.

quote:

Originally posted by Hot Core:
I'm not a fan of the Stoney Point/Hornady Thingies. Way too prone for error and non-repeatable measurements.

quote:

Originally posted by cjaholic:
...What is the best way to measure BSD? How much should I change it at a time?

That would be using the old, time-proven, never-fail, easily-repeatable, Cleaning Rod Method. Once you determine the OCL for the Kiss-the-Lands distance, convert from OCL to ODL and it is easy to make the changes to Seating Depth.

Try changing the Seating Depth 0.010" or even 0.005" to Fine Tune your Final Load.

Best of luck to you.

WOW, very nice answer. I like it.